Conventionally, in a magnetic levitation transportation system ground coil unit, a mounting bush is disposed so that the central axis of a hole thereof is parallel to the central axis of a coil conductor that is annularly wound, and a reinforcing glass fiber mat is laminated in a center line direction of the hole of the bush. The outermost layer of the reinforcing glass fiber mat is located so as to cover the coil conductor from two sides. Furthermore, a flange portion in which the bush is embedded is formed to be thin (for example, refer to Patent Document 1).
Patent Document 1: the Japanese Patent Publication (unexamined) No. 113107/1999 (Page 4, FIGS. 1 and 2)